1. Field of the Invention
This invention relates to structures for improving the aerodynamic profile of vehicles, especially for the front end of a trailer box in a tractor-trailer combination.
2. Description of Related Art
The amount of power needed to move a vehicle over land or through the air increases with the speed of the vehicle due to aerodynamic drag. The amount of power necessary to overcome aerodynamic drag directly translates into increased fuel consumption, and thus cost of operation.
A variety of innovations aimed at reducing the aerodynamic drag of various transport vehicles, including tractor-trailer combinations, have been introduced in the prior art. These include efforts to make the hood, windscreen, fenders etc. more streamlined in form, as well as by adding fairings to the cab roof, and in some cases, to the trailer box.
U.S. Pat. No. 6,799,791 discloses a vehicle fairing structure that may be deployed on the rear of a trailer box. While this fairing structure significantly reduces drag at the rear end of the trailer box, a significant amount of drag is also associated with the front of the trailer box where there is known to be an area of high pressure and relatively stagnant air approximately at the middle of the forward vertical face of the trailer cab. In general, the present inventors believe that the aerodynamic drag arising as a result of the gap between the tractor cab and trailer increases with the size of the gap (i.e., the distance between the rear of the tractor cab or roof fairing structure and the leading edge of the trailer box).
Accordingly, fairing structures designed to direct airflow around the gap have not been completely successful. On the one hand, known fairing structures for the forward face of a trailer box can be bulky and complex, involving moving parts. They may be difficult to install or impede access to important parts of the rig. A less obtrusive fairing structure, on the other hand, may be less effective in redirecting wind and more susceptible to the negative effects of crosswind conditions. Accordingly, there continues to be a need for fairing structures that effectively and elegantly address the problem of aerodynamic drag at the leading forward face of a trailer box in a tractor-trailer combination.
A system incorporating a fairing structure according to the invention is disclosed in U.S. Provisional Application No. 60/844,442, and in a non-provisional application claiming priority thereto and filed concurrently herewith. The aforesaid patent and applications (U.S. Pat. No. 6,799,791, Provisional Application No. 60/844,442 and the non-provisional application Ser. No. 11/684,104, now U.S. Pat. No. 7,404,592 filed herewith are incorporated by reference herein.